Sensata s Pressure and Temperature Sensor for R744 AC applications: a sensor that makes sense Renske Eissens
Content Part 1 Introduction Sensata Technologies Cabin Comfort Solutions Part 2 Why Sensors? R744 AC Sensor solutions Digital output compared to analog Customer choices Summary 2
Introduction Renske Eissens Product Manager Cabin Comfort sensor solutions Based in Almelo, The Netherlands Email: r-eissens@sensata.com Phone: +31 546 879 465 3
Sensata At A Glance Leading supplier of sensors and electrical protection with revenue over $1 billion in 2006 61% Sensors 39% Electrical Protection Technical expertise and proven capabilities Global presence with more than 10,000 employees Cost advantage through volume scale and best cost producing sites 50% Automotive 10% Others 14% Industrial 19% Appliances and HVAC 7% Heavy vehicle/ Off-Road
Cabin Comfort sensor solutions Pressure sensors Combined pressure and temperature sensors Optical (Solar, Twilight, Tunnel) Humidity Defogging Air Quality Comfort and Safety Comfort and Air Quality Comfort and Fuel Economy 5
Why sensors? R134a AC >> R744 AC Needed information Pressure Pressure + Temperature (Optional Temperature) Used for FAN control same Over pressure protection same + temperature Cooling performance same COP* optimization Leakage detection/ diagnostics Heat pump control Sensor Technology Capacitive Ceramic Strain Gauges, hermetic design Experience In production since Technology known within 1987: sold over 150MIO! Sensata; samples available WW market leader Already NOMINATED today! * COP: coefficient of performance Note: the end use of the sensor is in some cases dependent on several other component choices within an AC system, e.g. type of expansion valve) 6
R744 AC Sensor solutions Dual Analog LIN PWM Accuracy Pressure Temperature Response time Pressure Temperature Envelope Needed pins/ wires (3,4 or5) Connector type others LIN = digital signal; Local Interconnected Network PWM = digital signal, Pulse With Modulation 7
Accuracy of LIN versus analog (1/4) Sensata believes that on system level, a LIN approach can offer almost double the accuracy compared to a dual analog P+T sensor The Sensata LIN solution offers: +/-1.0 2.0 bar pressure accuracy from 0 170 bar +/-3 o C temperature accuracy @ 0 o C, 25 o C and 155 o C Pressure and temperature response time < 7.5ms System error for LIN : Sensing element error Analog preprocessing error ADC error (sensor ASIC) Digital domain System error for dual analog : Sensing element error Analog preprocessing error ADC error (ECU) The next 2 slides illustrate this with simplified block schematics Additional errors for analog interface Parasitic effects cabling & passives Noise, EMC Analog output stage ASIC 8
P-Accuracy of LIN versus analog (2/4) Sensor Cable ECU SE ADC / DSP Digital communication ECU Noise V+ SE Analog communication ECU Sensor Cable ECU 9
T-Accuracy of LIN versus analog (3/4) Sensor Cable ECU NTC ADC DSP LIN REF Digital communication ECU Noise V+ ECU Analog communication NTC Sensor Cable ECU 10
Overview LIN versus Analog LIN offers higher accuracy over the full pressure and temperature range LIN has a fast response time Lower cost in overall system and cabeling Less EMC sensitivity Additional embedded diagnostics 11
Customer choices type of signal preferred (LIN, PWM, Analog) pressure accuracy temperature accuracy preferable size of the sensor response time test specifications total cost at system level Sensata s engineering team leaders ready to meet demanding requirements: Electrical Engineering Mechanical Engineering Tim Tiek Werner Kleissen Title Design Engineer Electronics Title Design Engineer R744 P+T Phone +31 (0) 546 879470 Phone +31 (0) 546 879 557 Mail t-tiek@sensata.com Mail w-kleissen@sensata.com 12
a sensor that makes sense enables optimized AC efficiency (cooling performance) helps maximizing the COP > improves Fuel Economy and less CO 2 Emission makes it possible to diagnose filling rate/ leakage detection protects components like the compressor and gas-cooler for high pressure and temperatures enables heat pump functionality And, is available today! 13
Thank You 14